When it is, why we observe it and more about the vernal equinox

By Mackenzie Schmidt
March 19, 2018 01:28 PM
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It may not feel like it in many parts of the country, but the first day of spring is finally here!

The official start of the season, also known as the spring equinox or vernal equinox, is Tuesday, March 20 at 12:15PM.

The event, which always falls on either March 20 or 21, marks one of the two days each year that night and day are almost exactly equal in length everywhere on earth — the other is the autumnal equinox on September 22.

On the equinox, the earth’s position in relation to the sun causes the sun to pass directly overhead at the equator, the Farmer’s Almanac explains. It’s also the only day that the sun rises due east and sets due west at that spot.

While the northern hemisphere will begin to tilt toward the sun after March 20, signaling the start of spring, the southern hemisphere begins to tilt away from the sun, marking the beginning of fall there.

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Groups around the world mark the date with celebrations.

Easter and Passover both occur close to the equinox. In China, many people take part in a game of egg balancing to mark the time of new life. And in Iran, the date marks the Persian New Year and kicks off the festival of Nowruz, which is celebrated in several countries in the region.

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For practitioners of some ancient religions that worship nature, including pagans and druids, it’s an important day known as Ostara. Many people still gather at Stone Henge in the U.K. to watch the sun rise over the mysterious site.

The equinoxes aren’t the only dates that we look to in order to determine the first day of the new season. Meteorologists use weather patterns and temperature cycles to mark the seasons, according to the Farmer’s Almanac. By their calendar, spring has already sprung (March 1 was the first day) and will end on May 31.

The vernal equinox is far less controversial than another marker of spring in the U.S.: daylight saving time. The annual tradition of setting clocks ahead one hour to make the most of the daylight during summer is increasingly controversial with many states looking to abolish the practice.